Page 27 - Noninvasive Diagnostic Techniques for the Detection of Skin Cancers
P. 27

thus increasing the number of melanomas that are identified and sent for biopsy, while reducing
               the number of unnecessary biopsies. It may even allow melanomas to be identified at earlier
               stages which could lead to better outcomes.
                   Only one RCT examined this posited advantage of increased diagnostic accuracy of
               dermoscopy compared with naked eye examination. This RCT compared dermoscopic
               evaluation and naked-eye examination in 73 primary care physicians in Italy and Spain and
               inferred the effect of the addition of dermoscopy on the likelihood that a primary care physician
                                                                                                55
               would fail to refer a patient with suspicious skin lesions for a second expert opinion.
                   One RCT of 913 patients in Italy examined the downstream effect on the number of skin
               lesion excised for diagnostic verification with the addition of dermoscopy in a pigmented lesion
                     56
               clinic.
                   The use of dermoscopy may help to allay patient anxiety as one survey reported that more
               than half of the dermatologists queried responded that dermoscopy was effective in reducing
                                57
               patients’ anxiety.
                   One author suggested that followup examination using digital dermoscopy would allow for
                                                    58
               the detection of early stage melanoma.  We did not identify any controlled studies examining
               the use of dermoscopy to increase the detection rate of early stage melanoma. The studies on
               early melanoma identified by this brief were largely confined to the use of algorithms or
               classifiers of dermoscopic images to differentiate early melanoma from other stages of
               melanoma.

               Theoretical Disadvantages
                   The use of dermoscopy requires training and this may be considered a theoretical
               disadvantage for those who are not willing to invest in the time and effort to learn and master this
               technique. Based on our key informant interviews, we were informed that one of the main
               challenges to the use of dermoscopy lies in the training of nonexperts in its technique. The level
               of training and experience of the user may well determine the effectiveness of dermoscopy. A
               review paper recommended that dermoscopy should be used by experts to increase test
                        58
               accuracy.
                   The time necessary to complete an examination using the technique may be considered a
               negative factor in its use. In one study, almost one-third of dermatologists thought that the use of
                                                    57
               dermoscopy was too time consuming.  An RCT found that performing a complete skin
               examination with dermoscopy took significantly longer compared with a complete skin
               examination without dermoscopy (median time was 142 vs. 72 seconds, respectively;
                         59
               P<0.001).  Although one key informant suggested that since the total time required for a
               thorough complete skin examination (with or without dermoscopy) was generally less than 3
               minutes, it is not an reasonable amount of time considering that it could potentially prevent the
               morbidity and mortality associated with skin cancer. Another comparative study found that the
               use of dermoscopy is more time consuming compared with total body photography. The time
               spent at initial visit was 30 to 50 minutes for dermoscopic photographs and 20 to 30 minutes for
               TBP. Follow-up visit time was also longer with dermoscopic photographs lasting 30 to 50
                                                                14
               minutes compared with 10 to 20 minutes for TBP.
                   No study systematically assessed harms to either the patients or the operators from the use of
               dermoscope. Unintended effects from the use of dermoscope were described in two case reports.
               One case report described a patient who developed allergic contact dermatitis after exposure to
                                                                          60
               dermoscopy immersion oil contaminated with cedarwood oil.  The other described a




                                                             18
   22   23   24   25   26   27   28   29   30   31   32